Furnace



w. 7 6 6, 1 L A T E Y A R vG H. o.

April 24, 192s.

FURNACE Filed March 5. 927

2 Sheets-Sheet l April 24, 192s.

O. H. GRAY ET AL FURNACE Filed March 5. 1927 2 Sheets-Sheet 2 Patented Apr. 24, 192s.

UNiTi-:D STATESA PATENT' orly-'ice'.

OWEN H. GRAY ANDCHABLEB E. MUBDOCK, OSALT LAKE CITY, UTAH, ASSIGNOBS TO GRAY MURDOCK MFG. CO., OF SALT LAKE CITY,UTAH, A CORPORATION OF UTAH.

rUnNAcn.

Application led March 3, 1827. Serial 110.172,260.

This invention relates to furnaces and more particularly to an improved automatic Stoker and control therefor.

The present invention may be character- 6 ized as an improvement upon the automatic `furnaces illustrated and described in Babcock United States Letters Patent Nos. 1,386,698 and 1,420,091, issued August 9, 1921, and June 20, 1922, res ect'ively, and its 10 objects are the provision o a generally'm'- proved land simplified stoker and control that may be economically produced and conveniently installed without altering the furnaceand which is compact, simple, sturdy and reliable in operation.

. the invention is not limited to such use, but

While the particular 4embodiment which we shall hereinafter describe in connection with the drawings is particularly adapted for domestic use, it is to be understood that may be employed wherever found suitable or desirable.

We have found that the amount of heat given out by the furnace and, therefore, .the

temperature of the house, for example, be-

ing heated, can be controlled without opening or closing the dampers and that the complicated and delicate mechanical parts formerly used forthat'purpose may be en- 80 tirely omitted without affecting the results.

According to our resent invention, we obtain full and satis actory control of the fire and temperature of the house automatically by the rate of fuel feed, the interval of time between feedings and the length of check draft closed and the lower draft open time that each feeding lasts, all as regulated by -the` clock mechanism and thermostat which form a part of our presentl Stoker and control. Ve provide for leaving the to an extent which may be determined. by a few tests, that is, opened sufficiently that the fire is nottoolslggish and not so` wide that the coal or .fuel is entirely consumed and the fire extinguished between intervals of fuel feed. w y vThe-invention is illustrated in u Fig. 1 is aside elevational view of an enibodiment of our invent-ion:

Fig'. 2 is a f nt elevational ,view of the same;

Fig. 3 is a transverse 'section through the upper fuel chute and feed'means taken on the line 3.-?) of Fig. 1 ;P

Fig. 4 1s a similar view through the lower fuel chute and fuel feed means taken onV Fig. is anfend view of the chute and slide shown 1n.Fig.7.

Referring to the drawings, we have shown more or less illustratively at 5 the"`furnace,

the amount of heat given out by which the present invention provides for controlling. Except with reference to controlling same Without opening and closing the dampers, the details of the furnace 5,- per se, form no art of the resent invention which is equaly applica le to various furnaces. The lower main draft is designated at 6 and the upper choke draft is designatedr at 7 The stoker shown comprises a hopper 10 'with two feed troughsl or chutes 11 and 12, each having a slide 1n its'bottom for moving vthe coal or other fuel forward through the fire door 13 of the furnace 5 and dropping it upon the grate e14 inthe fire pot-15 within the furnace. The grate 14 may be of any standard or preferredforml suitable. forburning the. fuel that is employed. The in` vention is adapted to use slack or small sized coal, although itis not limited to use with any particular-sort'of fuel."

The upper chute 11 underlies and receives the coal or'fother fuel from the outlet 16 from the bottom of the hopper 10. In the bottom of the' chute 11 is a reciprocating slidelB. The slide '18 is reciprocated "or moved back and forth to deliverthe coal from the chute 11 to the chute 12, by a rod i the front end of the chute 1l andreceives vthe coal therefrom as it is delivered by-the slide 18. This lower chute 12 opens through the lire door 13 into the furnace and discharges the coal preferably at about the cen- 'ter of the fire box, althougli ..this may be varied. The chute 12 may, for. example, be made up of two supplemental'sections with the interior of 'one aligned with the interior of the other and in open communication therewith through an opening in the door 13. The adjacent ends of the sections 23 i and 24 may be ianged at 25 and suitably joined with the door 13 secured between them. The inner section 23 ispreferably formed. of cast iron and constitutes a cast iron spout which is not readily burned.4 od and is adapted for its disposition within the furnace and for delivering the coal thereto.

ln the bottom of the chute 12 is a reciprocating slide 26. lln Figs. 1, 2 and 4 this slide is shown as formed of cast'iron angle barsl secured back to back. The outer end of the slide 26 passes out from the outer end of the chute 12 through a st-uiling boX 28 which maybe lilled with cotton waste so that the spill of coal dust 1s practically if not entirely eliminated. The inner end 29 of the angle iron,` slide `26 never, in its reciprocating or back and forth movement, reaches the in ner end of the chute 12. It preferably never comes closer than 3 or 4 inches from the end of the spout 23 and is therefore never exposed to the direct action of the fire.- Thus We provide a spout. construction which is adapted to be-'exposedto the firel within the furnace and 'we protectfthe improved slide 26 from exposure at all tinies'hythe spout 23. vThe fire door 13 is shown as being clamped between the two halves of the lower chute 12.

In Figs. 7 and 8 wehave shown another form of slide for the lower chute. The slide in this instance comprises three pieces 100, 101 and 102 of standard iron or other suitable pipe. This round type plunger has certain advantages over the angle iron slide and'when same is turned truevon the outside and fitted a'crurately to a circular'hold 103 in the back of the chute 23. allows practically no dust whatever to spill out through the back.4

A motor 32 through suitable connections oscillates or rocks an arm 33 alternately in opposite directions about its pivot 34 (Fig.

` retracer 1), the arm 33 being connected to reciprocate or move the slides 18 and 26 alternately in opposite directions, moving the slide 18 inwardly toward the furnace 5 when the slide 26 is being moved outwardly and viceversa. The particular connections between the motor 32 and the arm 33 may be varied.

--Those shown comprise the, speed reducing pulleys 36 and 37, belt 38, shaft 39, worm 40, lworm wheel 42, shaft 43 and the eccentric 44 which is connected through a link 45 with the arm 33. The upper end of the arm 33 engages between a pair of nuts or abutments 48 threaded upon the outer end of the rod 20, these nuts or abutments 48 being adjustable upon the rod 20 to adjust t-he movement of the upper slide 18 and comprises (Fig. 5) a hell ringing transpformer 56, electro-magnet 58 comprising a winding 59 land core 60, an inverted generally il.shaped bell crank leverl 62 pivoted at 63 with'the mercury tube or merooid tube 64 mounted upon its generally horizontal arm 65, time or clock controlled cam 66 and the single contact thermostat 68 comprising the thermostatic leaf 69 of any suitable or preferred form and the cooperating contact 70 adjustably mounted at 72 for adjusting the space or gap between it and the leaf 69.

The motor 32 is connected through con'- ductors 73 and 74 across the primary winding 75 of the transformer 56. One side of the secondary winding 76 is connected 4 through a conductor 77 with one end of the .winding 59 of the electromagnet 58 and the AThe tube 64'contains a quantity of mercury 88 which immerses and electrically connects the terminals 83 and 84Vwhen the tube is tilted by clockwise rocking of the bell crank 62, but which leaves the terminals 83 and 84 unconnected when the tube is returned to the position shown.

The operation of the invention is as follows :-l

At regular intervals of time, for example, .once an hour or once every half hour, the cam 66 is rotated by suitable clock mechanism and engages the depending arm of the rocker or bell crank 62, pressing it to the left (Fig. 5) .and thus tilting the mercoid tube 64 so that the mercury will roll down into contact with ,the terminals 83 and 84 connecting said terminals and closing ,the circuit from the 11G-volt supply lines through the motor 32 which drives the coal feeding mechanism. The circuit through the secondary Winding of' the small transformerv 56 is also closed, which causes the secondary of the transformer to impress a voltage of 12 volts, in a particular actual embodiment of the invention, on the circuit through the thermostat 68 and holding magnet 58.

The thermostat 68 is located, for example,

- in some room or other place to which heat is being supplied and the temperature of the air regulated and when the temperature is below the point for which the thermostat is set, this point being adjustableby adjusting contact 70, the therrnostatcontact will be closed so that current will fiow through the electromagnet 58 and thismagnet will then hold the rocker lever 62 in its tilted position even after thecam 66 has passed out of reach of the rockerv lever. This keeps the main circuit closed through the mercoid tube 64 and therefore keeps the Stoker feeding coal into the furnace until the air temperature at thermostat 68 rises and causes the contact at that point to be broken.

As soon` as the contact'at the thermostat 68 is broken, the electromagnet 58 releases the Vrocker lever 62 which then swings back to its normal vertlcal position and causes the mercury 88 to roll to the left and openthe circuits through vthe ymotor and transformer. This stops the feeding of the'coal and all fiow of current in any part of the apparatus. f`

If the temperature of the air adjacent the thermostat 68 is up to or above thetemperature for which the thermostat is set, the contact at the thermostat will be opened and no current will flow through the electromagnet 58 even though the main circuit is closed by the tilting ofthe mercoid tube 64 under the time action of the' cam 66. In other words, when theliouse is warm enough, the motor,Y circuit will be o ened and closed and the fuel feed operate controlled cam 66 and the durationy of the periodic fuel feedings will be only so long as the cam 66 is in cooperation with the arm 62.

. The time mechanism will, for example, cause solely -by the time.

lire alive. Whenever the temperature does drop, the thermostat 68 closes and the first time that the time mechanism tilts the tube 64 and starts the Stoker operation, the electromagnet 58 will continue it in operation `until the temperature is restored and the thermostat contact 68 opens. The time mechanism provides definite periodic fuel feedings, and as the temperature requirements demand, the thermostat increases the feedings and decreases the intervals between them.

Throughout the operation of the furnace.

the main and check drafts 6 and 7 have fixedy settings and the furnace is controlled solely `by the control of the fuel feed thereto. The

check draft is closed and remains closed throughout the different conditions of operation and the main lower draft 6 is opened to an extent determined by a few tests. It is opened enough that the fire is not too sluggish and not so wide that the coal or 5 fuel is entirely consumed andv the` fire extinguished between intervals of fuel feed and upon -obtaining the proper opening to provide this condition that setting of the lower draft 6 remains fixed throughout thefoperationof the furnace. No filrther change in the draft is required. v

a We have also found that in some instances an improved combustion may be secured by means of a moderate blast of air directed onto the fire from above. For this purpose the motor 32 Imay drive a relatively small fan such as that employed in a vacuum cleaner. This fan is designated at 90 in Fig. 1 and furnishes air which is supplied or introduced-into the furnace by means of a short piece of one and one-half inch hose connected through a piece of one and onequarter inch ironA pipe 92 which passes through the fire door 14 at apoint immeofair is thrown onto the-fire at about its center, thus assuring a good "supply of air hfor combustion, even though the grate be ow might be lentirely clogged with ashes and clnders. l Y

This air jet, while desirable in some cases,

maybe omitted, and We therefore do not intend to be inany Way limited to operation with such a jet.

In some instances, it may also be desirable to provide an automatic limit to the pressure ofthe steam or temperature of the water, Whether the air in the house tol be heated has reached the normal degree, or not. In that in some installations the pressureof the-steam or temperature of the Water may reach dangerous points before the air in the house has had time to Warm up, We provide (F ig. 6) a device designated at 95,' which may be operated by the temperature of the Water or pressure of the steam to open the circuit of the motor irrespective of the thermostat 68. This' device is designated at 95 in Fig. 6 and is shown as connected by means of the conductor 73 in series with the motor 32. This device may be any one of several already on the market or ofany-other suitabletype, and may be used in addition to the automatic control,r as already described, so that when either the air in the house, or the Water in the boiler gets too hot, the fuel feed is stopped.

We claim l. In a furnace the combination of a mechanical fuel feed, means for periodically operating said fuel feed Qindependently of temperature requirements, and means for varying the duration of the zperiodic fuel feeding operations produced by said first means and the intervals between said operations With the temperature requirements 'of the furnace.

2. 'The combination, with a furnace, of amechanical fuel feed thereto, time controlled means for operating said fuel feed to supply fuel to the furnace at periodic intervals, irrespective of temperature requirements, and a single contact thermostat controlling said fuel feed to vary the fuel supply according to the temperature requirements of the furnace.

3. The combination, with a furnace` of a mechanical fuel feed for feeding fuel into the furnace, electrically operating means for operating said fuel feed, time controlled means 'controlling the operation of saidA operating means to operate fuel feed periodically over definite intervals and lthermostatically controlled means for varying the duration of the fuel feeding intervals and the duration of the intervals betweensaid fuel feedings with the temperature requirements of the furnace.

4. The combination, with a. furnace, of a mechanical fuel feed for feeding fuel into the furnace, a driving motor for said fuelfeed,a motor circuit, a circuit having a thermostat, a bell rlngmg transformer having its primary 1n one of said circuitsl 'and its secondary in the other circuit, a mercury, VY- bulb-contact device, a rocker arm pivotallyTply line therefrom, a mechanical fuel feed l the furnace, a driving motor for said fuel feed, a ,motor circuit, a circuit having a ther.- mostat, a bell ringing transformer having its primary in one of said circuits and its secondary in the other circuit, a mercury bulb contact device, a rocker arm pivotally mounted and adapted to tilt said bulb to close and lopen the motor circuit, a time control device for tilting said arm atdefinite periodic intervals irrespective of temperature requirements, electromagnetic means controlled by the temperature requirements of ,f the furnace through said .thermostat and cooperating with said rocker arm to hold same tilted after tiltin by said time controlled means for increasing the duration of the intervals-of the' fuel feed to the furnace, and means operated by the pressure of the steam or temperature of the water for stopping the A fuel feed independently of the thermostat.

6. In a'furnace, the combination of a mechanical fuel feed, `'time controlled means for -periodically operating said fuel yfeed independently of temperature requirements and temperature controlled means for vary ing the duration of the periodic fuel feeding operations produced by said time controlled means and the intervals between said operations with the temperature requirements of the furnace.

7. In 'a furnace, the combination of ame. i

chanical fuel feed, time controlled means` for periodically operating said fuel feed independently of temperature requirements, and temperature controlled means for varying the duration of the periodic fuelfeeding operations produced by saidl time controlled Ameans and the intervals between said operations with the temperature vrequirements of the furnace, said temperature controlled means beingv located outside the furnace and adjacent the place to which heat is supplied by said furnace.

8. In a furnace, the combination of ame-v chanical `fuel feed,- means for periodically operating said fuel feed and a second means operated to vary the operation of said first means with the temperature requirements of 'the furnace.

9. Inf-combination, a furnace, a heat supdevice for said furnace, means for periodimeans for varying the duration of the pe.

riodic fuel .feeding operations produced by said device and the intervals between said operations with the temperature requirements of the furnace and means operated by the temperature of the fluid .in the heat sup'- ply ine for stopping the fuel feed means at a predetermined limit.

In Witness whereof, We hereunto set our vhands this 23rd day of February, 1927.

OWEN' H. GRAY. CHARLES E. MURDooK. 

